It is likely to start with a James Brown wail, an ever-ascending, caterwauling screech that knocks away any remnants of the morning haze. J.B. is telling you he feels good. Now so do you. Since 1986, Felix Hernandez has been starting Saturdays this way for thousands of metro-area soul-music fans whose listening tastes have been all but shut out by commercial radio. Hernandez's own classic radio patter coaxes and celebrates as he spins a play list that is the old made new: Eddie Holman's haunting "This Can't Be True"; Bertha Tillman's ethereal "Oh My Angel"; Little Willie John's superb "No Regrets." Even if these names mean nothing to you, you should still stop by. It is how to start the weekend.